In the wake of the tragic shooting at a midnight premiere of The Dark Night Returns, some of the most vivid descriptions of the scene are coming from first responders themselves.More >>

AURORA, CO (RNN) - The public got its first glimpse of the man who is accused of killing 12 people in a shocking mass shooting on the night of the premiere of the movie, The Dark Knight Rises.

James Eagan Holmes made his first court appearance Monday, and will be formally charged in the shootings on Monday, July 30. District Attorney Carol Chambers told reporters there was enough probable cause to charge him with first-degree murder, at minimum.

A no bond hold was issued by the judge, meaning Holmes will be held without bail at least until a later hearing. He was also appointed a public defender.

The judge granted prosecutors an extension to file charges against Holmes. Typically, prosecutors formally file charges within 72 hours of an initial court appearance. The extension gives the state four more days to sort through the massive case.

Friday's massacre has been called one of the worst mass shooting in U.S. history.

District Attorney Carol Chambers said her office may pursue the death penalty against Holmes, although she told reporters she would speak with the victims before making her final decision. She has 60 days to make her decision.

Holmes' facial expressions throughout the hearing made it unclear how much the 24-year-old with bright, sunburst orange and yellow hair understood. He periodically widened his eyes without any apparent provocation from the court. He blinked quickly and constantly at some moments, while at others looked as though he was going to take a nap while the proceedings continued.

The strange behavior comes on top of reports of Holmes spitting at guards and "acting crazy," a former inmate who was released after Holmes was admitted to the Arapahoe Detention Center told the New York Daily News.

"He thinks he's acting in a movie," a jailhouse employer told the publication.

He also reportedly told police he was the Joker, a popular character who was prominently featured in the second installment of the latest Batman reboot, The Dark Knight.